Insensitive explosive composition and method of fracturing rock using an extrudable form of the composition

ABSTRACT

Insensitive explosive compositions were prepared by reacting di-isocyanate and/or poly-isocyanate monomers with an explosive diamine monomer. Prior to a final cure, the compositions are extrudable. The di-isocyanate monomers tend to produce tough, rubbery materials while polyfunctional monomers (i.e. having more than two isocyanate groups) tend to form rigid products. The extrudable form of the composition may be used in a variety of applications including rock fracturing.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 13/153,972entitled “Insensitive Explosive Composition and Method of FracturingRock using an Extrudable Form of the Composition,” filed Jun. 6, 2011,now allowed.

STATEMENT REGARDING FEDERAL RIGHTS

This invention was made with government support under Contract No.DE-AC52-06NA25396 awarded by the U.S. Department of Energy. Thegovernment has certain rights in the invention.

FIELD OF THE INVENTION

The present invention relates generally to an insensitive explosivecomposition that is a mixture of an explosive diamine monomer with a di-and/or poly-isocyanate monomer, to an insensitive explosive reactionproduct of a reaction between these monomers, and to a method offracturing rock that employs an extrudable explosive composition.

BACKGROUND OF THE INVENTION

Insensitive explosive compositions are often physical mixtures of a highexplosive compound embedded in a matrix of a polymeric binder (see, forexample: Lund et al., U.S. Pat. No. 5,529,649 “Insensitive HighPerformance Explosive Compositions”; Doll et al., U.S. Pat. No.6,648,998 “Reduced Sensitivity Melt-Cast Explosives”; Lee et al., U.S.Pat. No. 6,881,283, “Low Sensitivity Explosive Compositions”; Muller etal., U.S. Pat. No. 5,547,527, “Process for the Production ofDesensitized Explosives”; all incorporated by reference herein). Themixture of explosive and binder is typically a physical mixture thatrelies on relatively weak forces for adhesion between the explosive andthe binder.

SUMMARY OF THE INVENTION

The present invention provides an insensitive explosive composition. Thecomposition may be an explosive oligomeric or polymeric reaction productof an explosive diamine monomer with a di-isocyanate monomer, apoly-isocyanate monomer, or mixtures thereof. The monomers havingisocyanate groups may be alkyl di-isocyanate monomers, aryldi-isocyanate monomers, an alkyl poly-isocyanate monomers, arylpoly-isocyanate monomers. An embodiment explosive reaction product is anoligomer or polymer of 3,3′-diamino-4,4′-azoxyfurazan (“DAAF”) monomerand a di-isocyanate monomer. Another embodiment explosive reactionproduct is a crosslinked polymer of DAAF monomer and a poly-isocyanatemonomer.

An embodiment insensitive explosive composition is a reaction product ofa reaction of a di-isocyanate monomer with an explosive diamine monomer.As the compositions cures but prior to a final cure, the composition maybe extruded into a variety of shapes. After a final cure, thecomposition tends to be rubbery and tough.

Another embodiment is an explosive reaction product of a reaction of apoly-isocyanate monomer with an explosive diamine monomer. As thecomposition cures, but prior to a final cure, the composition may beextruded into a variety of shapes. After a final cure, the compositiontends to be rigid.

Yet another embodiment insensitive explosive composition is a reactionproduct between a di-isocyanate monomer, an explosive diamine monomer,and glycidyl azide polymer. As the composition cures, but prior to afinal cure, the composition may be extruded into a variety of shapes.

Still another embodiment insensitive explosive composition is a reactionproduct of between a poly-isocyanate monomer with an explosive diaminemonomer and a glycidyl azide polymer. As the composition cures, butprior to a final cure, the composition may be extruded into a variety ofshapes.

Another embodiment insensitive explosive composition is a reactionproduct between a di-isocyanate monomer, a poly-isocyanate monomer, anexplosive diamine monomer, and glycidyl azide polymer. As thecomposition cures, but prior to a final cure, the composition may beextruded into a variety of shapes.

The present invention is also concerned with fracturing rock. Anembodiment relates to extending a fracture network in rock by reactingan explosive diamine monomer with a monomer selected from an alkyldi-isocyanate monomer, an aryl di-isocyanate monomer, an alkylpoly-isocyanate monomer, an aryl poly-isocyanate monomer, a glycidylazide polymer, or mixtures thereof, to form an extrudable explosivecomposition, and sending the composition into fissures in rock, anddetonating the composition whilst it is in the rock fissures, therebyextending the fracture network in the rock.

DETAILED DESCRIPTION

This invention is concerned with relatively insensitive, explosivecompositions. Embodiment compositions include insensitive explosiveoligomeric or polymeric reaction products of reactions of explosivediamine monomers with di-isocyanate monomers and/or poly-isocyanatemonomers. Other embodiments include relatively insensitive explosivepolymeric reaction products of reactions of di-isocyanate monomers orpoly-isocyanate monomers with explosive diamine monomers and glycidylazide polymers, and un-polymerized mixtures of the explosive diaminemonomers with glycidyl azide polymers.

A di-isocyanate monomer is defined as an organic compound including twoisocyanate chemical groups. These are sometimes described asdifunctional. Embodiments of these monomers include alkyl di-isocyanatemonomers and aryl-di-isocyanate monomers.

A poly-isocyanate monomer is defined as an organic compound includingthree of more isocyanate chemical groups. These are sometimes referredto as polyfunctional, which means that the monomer has three of morefunctional groups (in this case, three of more isocyanate groups).Embodiments of these monomers include alkyl poly-isocyanate monomers andaryl poly-isocyanate monomers.

For the purposes of this invention, an insensitive explosive compositionis defined as an explosive composition that meets all of the followingthree criteria:

1) the explosive composition exhibits no reaction at the maximum heightof 320 centimeters in a standard Los Alamos National Laboratory (“LANL”)drop-weight impact test, which involves dropping a 2.5 kilogram weightonto a 40 milligram sample using standard Type 12 tooling;2) the explosive composition exhibits no reaction at the maximum load of360 Newtons in the Bundesanstalt für Materialprüfung (“BAM”) frictiontest, conducted in accordance with the UN Recommendations on theTransport of Dangerous Goods—Manual of Tests and Criteria, Section 13.5,Series 3 type (b) test prescriptions; and3) the explosive composition exhibits no reaction in the AlleghenyBallistics Laboratory (“ABL”) Electrostatic Discharge test at themaximum energy of 0.25 Joules.

In an embodiment, an insensitive explosive composition is a reactionproduct of an alkyl di-isocyanate monomer and an explosive diaminemonomer. The reaction product is a polyurethane (see, for example:Odian, Principles of Polymerization, 3^(rd) edition, John Wiley & Sons,Inc., New York, pp. 136-138, incorporated by reference herein), which isan alternating copolymer of the di-isocyanate monomer and the explosivediamine monomer. As they form, i.e. as they are curing, but prior to afinal cure, they may be extruded into a desired shape. At this stage,i.e. prior to the final cure, it is believed that the compositions areoligomers and/or polymers. After the final cure, the reaction producttends to be a tough, rubbery polymeric product that is also aninsensitive explosive composition. The extrudable form prior to thefinal cure is also an insensitive explosive composition.

In another embodiment, an insensitive explosive composition is areaction product of a catalyzed reaction of an alkyl poly-isocyanatemonomer and an explosive diamine monomer. The reaction products arepolyurethanes. When poly-isocyanates are used, the polyurethanes tend tobe cross-linked. As they form, i.e. as they are curing, but prior to afinal cure, they may be extruded into a desired shape. At this stage,i.e. prior to the final cure, it is believed that this form of thecomposition (i.e. an extrudable form) includes oligomers of theexplosive diamine monomer and the poly-isocyanate monomer. After thefinal cure, the reaction product tends to be a rigid polymer product.The rigidness is likely a result of crosslinking. Both the extrudableform and the rigid polymer product are insensitive explosivecompositions.

In a preferred embodiment, the explosive diamine monomer is3,3′-diamino-4,4′-azoxyfurazan (“DAAF”) (see, for example, Hiskey etal., U.S. Pat. No. 6,358,339, “Use of 3,3′-diamino-4,4′-azoxyfurazan and3,3′-diamino-4,4′-azofurazan as insensitive high explosive materials,”;Hiskey et al., U.S. Pat. No. 6,552,201, “Preparation of3,3′-diamino-4,4′-azofurazan,” both incorporated by reference herein).An embodiment explosive composition is, for example, an oligomer oralternating copolymer of DAAF monomer and a di-isocyanate monomer suchas, but not limited to,3-isocyanatomethyl-3,5,5-trimethylcyclohexyl-isocyanate which is alsoknown more commonly as isophorone isocyanate (“IPDI”). Anotherembodiment is an alternating copolymer of DAAF with an aryldi-isocyanate monomer such as, but not limited to,2,4-diisocyanato-1-methyl toluene, also known as toluene di-isocyanate.

An embodiment oligomeric or polymeric reaction product oftoluene-di-isocyanate monomer with DAAF is an insensitive explosivecomposition. Prior to a final cure, the material may be extruded. Theextrudable form is an insensitive explosive composition. The final curedreaction product is also an insensitive explosive composition with goodthermal stability and compatibility as determined under U.S. MilitaryStandard 1751A.

Another embodiment insensitive explosive composition is the mixture ofglycidyl azide polymer and DAAF, which react with di- and/orpoly-isocyanate monomers to produce an insensitive explosive polymericreaction products. In an embodiment wherein the di-isocyanate monomerwas IPDI, the final cured insensitive explosive reaction product wasfound to be a tough, flexible rubber.

Another embodiment insensitive explosive composition is the mixture ofR45M (a commercially available hydroxyl-terminated polybutadiene(“HTPB”)) and DAAF, which produces a reaction product with adi-isocyanate monomer or poly-isocyanate monomer. The reaction isbelieved to involve reaction of an isocyanate group from a monomer withan amine from the DAAF, and reaction of the other isocyanate group fromthe monomer with GAP. An example is the reaction product of R45M HTPBand DAAF with 1-isocyanato-4-[(4-isocyanatophenyl)methyl]benzene(“MDI”).

A benefit of the insensitive nature of these explosive compositions isthat they can be more safely subjected to the types of processingconditions typically required for extrudable explosives. Another benefitrelates to an expanded role of extrudable explosives in applications inwhich the sensitivity of current explosive formulations restricts orprohibits the use of extrudable explosives. Another benefit relates tothe mechanical properties of the explosive composition of thisinvention, which allows a range of applications in which enhancedmechanical properties of these compositions may be exploited for use asstructural members or to improve mechanical properties of a system,device, or product.

The compositions of this invention are useful for a variety ofapplications. Military and police entry teams currently use extrudableexplosives in forced entry situations wherein the extrudable material isforced into door crevices and other openings using a common caulkinggun. The insensitive explosive compositions of this invention could beused for these purposes with improved safety.

Extrudable explosives are also used for Explosive Ordnance Disposal(“EOD”). The insensitive explosive compositions of this invention couldbe used for EOD with improved safety.

The insensitive explosive compositions of this invention could be usedin mining applications. The booster charge used in commercial blastingoperations should be physically durable enough to withstand falls of 60meters or more into bore holes that are subsequently loaded with bulkexplosives. Booster explosives fabricated from embodiment insensitiveexplosive compositions of this invention display greatly improvedmechanical toughness, together with insensitivity to impact and otherstimuli. Therefore, the insensitive extrudable explosive compositions ofthis invention may be used as booster charges for commercial blastingoperations.

Seismic prospecting with explosives involves detonation of a smallcharge that may be placed underwater, in a shallow wellbore, or may beextruded (e.g. by injection) into small openings. An array of detectorsis utilized to collect information from the seismic wave propagating outfrom this point source. Selection of explosives suited for thistechnique has long been a subject of interest (see, for example: Johnsonet al., Geophysics, 1935, vol. 1(2), pp. 228-238, incorporated byreference). These applications may benefit from an explosive with smallcritical diameter, which embodiment insensitive explosive compositionsof this invention have. The extrudable, relatively insensitive explosivecompositions of this invention may be used for these exploratory mappingapplications.

Insensitive explosive compositions of this invention may also be used inwell completion. The extrudable insensitive explosive compositions ofthis invention may also be used in oil well completion devices in whichthe explosive may be injected into a charge assembly remotely. Wellcompletion techniques using explosive compositions have been the subjectof extensive research; the first recorded shot was conducted in 1865.Ford et al. in U.S. Pat. No. 4,391,337, incorporated herein byreference, reported using a high-velocity jet to initiate fractures inthe production zone of a well. A propellant gas was used to extend thefractures.

In hydraulic fracturing of oil and gas wells, a fluid under highpressure is injected to create fractures in rock, which are then“propped” open by a proppant such as sand or other particulatematerials. One commonly used proppant is U.S. Standard Sieve size #20sand, which has a typical particle diameter in a range of 0.710-0.850millimeters. A complication in hydraulic fracturing is that not allfractures are adequately loaded with proppant. Inadequately proppedfractures may close when the hydraulic pressure is released. Therefore,these fractures are not productive.

The insensitive explosive compositions of this invention may be used asa hydraulic working fluid that is extruded (e.g. by injection under highpressure) into rock fractures, potentially traveling a considerabledistance from the wellbore. Once extruded into the fractures, thecomposition may be subsequently cured in situ under hydraulic pressureto form a self-propping matrix. Alternatively, the composition may beleft uncured and used in combination with a conventional proppant.Subsequent detonation of the explosive-filled fracture pattern willproduce an extended volume of productive material between these cracks,and extending outwards into adjacent rock.

Previous explosive well completion methods have traditionally focused oncharges which are detonated within the wellbore, sometimes resulting incompaction of the surrounding geologic material and reduction of wellyield. Methods of timing successive small explosive charges within thewellbore to generate wave interactions in adjacent rock have beendeveloped, as described in the “technology update” article entitled“Well Stimulation/Completion Using High Explosives, Journal of PetroleumTechnology 58(2), 1996 pp. 22-24, incorporated by reference herein. Inthis application, an embodiment extrudable insensitive explosivecomposition would be extruded into rock fractures outside the well caseby methods intended to exclude the explosive composition from of themain body of the wellbore. Controlled timing of detonations in adjacentfracture patterns may be exploited in order to generate stress waveinteractions in the volume of material between and extending outwardfrom the explosively-filled fractures, which are favorable to producingan extended volume of dilatancy in the surrounding rock.

DAAF has a critical diameter between 1 and 1.5 millimeter, which meansthat it will propagate a steady detonation unconfined in a rightcircular cylinder of this dimension, so the critical thickness of anunconfined planar form is expected to be on the order of 0.63millimeters. When confined in rock this dimension will be reduced,allowing detonation to propagate in small sizes. A critical dimension ofthis size combined with insensitivity to mechanical stimuli is uncommon.The extrudable, insensitive explosive compositions of this invention arepolymerizable viscous fluids. It is believed that these extrudable,polymerizable, insensitive explosive compositions are the first thatalso possess a small critical diameter.

The Examples below illustrate some non-limiting embodiments. AlthoughExample 1 does not include a di-isocyanate or poly-isocyanate monomer,it does demonstrate a reaction of DAAF with an isocyanate compound.Dibutyltin dilaurate (“DBTDL”) was the catalyst generally employed,although other catalysts suitable for the reaction may be used instead.The polymerization may also proceed uncatalyzed at higher temperatures.Unless otherwise indicated, all reactions were conducted withoutsolvent, which is typical for solid propellant cast-cure systems.

Example 1

A solution of 212 milligrams of 4,4′-diamino-3,3′-azoxyfurazan (“DAAF”)in dry tetrahydrofuran in a jacketed round-bottomed flask was prepared.238 milligrams of phenyl isocyanate were added to the solution, followedby 1 milligram of dibutyltin dilaurate (“DBTDL”). The reaction vesselwas fitted with a thermometer, reflux condenser and magnetic stirrer.This reaction mixture was refluxed, then cooled to ambient temperatureand the reaction product isolated. Analysis of the reaction product byFourier transform infrared spectroscopy (“FTIR”), nuclear magneticresonance spectroscopy (“NMR”) and liquid chromatography—massspectroscopy (“LC-MS”) confirmed reaction of the phenyl isocyanate withDAAF. Both the mono- and diphenylurethane derivatives of DAAF wereobserved, together with a small amount of unreacted DAAF, trace amountsof unreacted phenyl isocyanate, and aniline.

Example 2

3-isocyanatomethyl-3,5,5-trimethylcyclohexyl-isocyanate (250 milligrams,“IPDI”) were combined with DAAF (250 milligrams) and a trace of DBTDLhaving a concentration of 1 mg/ml in dichloromethane. The product was arubbery solid. The product showed no reaction to impact, friction, andspark tests, and had a mild burn character to open flame. The reactionproduct was an insensitive explosive composition.

Example 3

DAAF (400 milligrams) was combined with3-isocyanatomethyl-3,5,5-trimethylcyclohexyl-isocyanate (5 milligrams)and 95 milligrams of a solution of a hydroxyl-terminated glycidyl azidepolymer known as “GAP 5227” in ethyl acetate (3M L15129, 40% in ethylacetate, GAP—ethyl acetate weight 237.5 mg) with trace of dibutyltindilaurate (target concentration is typically 0.001 to 0.005 percent byweight of the catalyst, from solution of 1 mg/ml DBTDL in methylenechloride). The reaction proceeded in approximately 1 hour at ambienttemperature. Solvent was removed by evaporation in fume hood atapproximately 50° C. overnight. The reaction product was a tough rubbermaterial that was also an insensitive explosive composition.

Example 4

DAAF (2.0 grams) was combined with GAP (1.88 g, 40% in ethyl acetate)and IPDI (25 mg) with approximately 1 milligram of DBTDL. The systemcured in approximately 1 hour at ambient temperature. The ethyl acetatewas removed by evaporation overnight in fume hood at ca. 50° C. Thereaction product was an insensitive explosive composition.

Example 5

A 5 gram batch composed of 4 grams DAAF, 950 milligrams of GAP (40% inethyl acetate) and 50 milligrams of IPDI and a trace of DBTDL wasreacted to form a solid reaction product that was an insensitiveexplosive composition.

Example 6

DAAF was reacted with DESMODUR N-100 (BAYER MATERIAL SCIENCE), which isa solvent-free aliphatic polyfunctional isocyanate based onhexamethylene di-isocyanate. DESMODUR N-100 has functionality ofapproximately 4 isocyanate groups and molecular weight of approximately478 g/mol. The total sample mass was 500 milligrams, composed of 212milligrams DAAF and 288 milligrams of DESMODUR N-100. Reaction proceededafter a trace amount of DBTDL (1 mg/ml in CH₂Cl₂) catalyst was addedwith stirring. After 1 hour at ambient temperature, the product was arigid, hard solid. The rigidness likely resulted from cross-links. Thereaction product was an insensitive explosive composition.

Example 7

DAAF (ATK THIOKOL) was dried in a vacuum oven at 50° C. A sample wasprepared that consisted of 1.25 g of this DAAF, 1.125 grams of GAP whichhad been previously stripped of ethyl acetate by vacuum distillation ina rotary evaporator, and 0.125 grams of IPDI with a trace of dibutyltindilaurate. The sample was mixed by hand and loaded into a disposable 10cc plastic syringe, which had been attached to a brass tube with insidediameter of 3 mm and length of 100 mm. The sample was extruded by handfrom the syringe into the tube, and it cured inside the tube. Both theextrudable composition and the final cured reaction product wereinsensitive explosive compositions.

Example 8

A DAAF/GAP/IPDI system composed of 70% DAAF was scaled up to a batchsize of 25 grams. The batch was composed of 17.5 grams of DAAF which hadbeen dried in a vacuum oven at 50° C., 7.116 grams of GAP previouslystripped of ethyl acetate by vacuum distillation in a rotary evaporatorand 0.384 grams of IPDI with 50 mg of DBTDL. A portion of this samplewas extruded into a brass tube with inside diameter of 3 mm and lengthof 100 mm. The sample was extruded by hand into the tube, and it curedinside the tube. Cure proceeded at ambient temperature over a few hoursand resulted in a hard, slightly rubbery solid. Both the extrudable formof the composition and the final cured, hard, slightly rubbery solidwere insensitive explosive compositions. The tube was then attached toan aluminum witness plate along with a Reynolds RP-3 detonator. About 20mg of SEMTEX 1H was used to couple the output of the detonator into thetest sample. The sample was detonated on a witness plate.

Example 9

4 grams of DAAF that was dried in a vacuum oven at 50° C. was combinedwith 4 grams GAP 5227 (also stripped of ethyl acetate and dried) and 2grams of tungsten carbide (W₂C), 0.2 grams of toluene di-isocyanate anda trace of DBTDL. This mixture was degassed on a shaker table under ahard vacuum as typically practiced in solid propellant formulation work,and loaded by hand into a brass tube having an internal diameter of 5.56mm and length of 150 mm. The resulting product exhibited a bulk densityof 1.95-2.00 glee. Both the extrudable material and the final curedsolid were insensitive explosive compositions. The sample was detonatedwith a Reynolds RP-3 detonator.

Example 10

A 500 milligram batch of DAAF and DESMODUR N-3200 (an aliphaticpolyfunctional isocyanate) in a 50:50 molar ratio was prepared with atrace of DBTDL. Product was a rigid, brittle solid. The cross-linksprovided by the polyfunctional isocyanate resulted in more rigidmaterial. The rigid reaction product was an insensitive explosivecomposition.

Example 11

A 500 milligram batch sample of 50:50 by weight DAAF with MDI(4,4′-methylene-bis-diphenyldi-isocyanate) was prepared with a trace ofDBTDL. The product was a rigid, brittle solid that was also aninsensitive explosive composition.

Example 12

A 500 milligram batch sample consisted of 250 milligrams DAAF, 225milligrams R45M HTPB (a hydroxyl-terminated polybutadiene) and 25milligrams of Desmodur N3200 with a trace of DBTDL. The reactioninitiated within a few minutes to yield a tough flexible rubber that wasin insensitive explosive composition.

Example 13

A 500 milligram batch sample that consisted of 250 milligrams DAAF, 225milligrams R45M HTPB (hydroxyl-terminated polybutadiene) and 25milligrams of MDI (4,4′-methylene-bis-diphenyl-di-isocyanate) wasprepared with a trace of DBTDL. The reaction initiated within a fewminutes to yield a tough flexible rubber that was an insensitiveexplosive composition.

Example 14

A 500 milligram sample that consisted of 250 milligrams DAAF, 200milligrams MDI (4,4′-methylene-bis-diphenyl-di-isocyanate) and 50milligrams glycerin was prepared with a trace of DBTDL. The reaction wascomplete within a few minutes. The reaction evolved heat. The productwas a rigid brittle solid. The increased crosslink density from thepolyol resulted in rigid solid that was an insensitive explosivecomposition.

Example 15

A sample was prepared by combining 250 milligrams DAAF with 25milligrams carbon (lampblack) and mixed under petroleum ether using anultrasonic probe for 30 seconds. The petroleum ether was allowed toevaporate and the resulting mixture was combined with 200 milligrams GAP5227 (dried), 25 milligrams MDI and a trace of DBTDL. The reaction wasallowed to proceed to form a reaction product that was a tough, flexiblerubber that was black in color and also an insensitive explosivecomposition.

Example 16

DAAF (ATK Thiokol) was recrystallized from DMSO and dried in a vacuumoven. 150 grams of this DAAF was mixed with 135 grams of solvent-freeGAP and 15 grams of 1-isocyanato-4-[(4-isocyanatophenyl)methyl]benzene(“MDI”) with 30 milligrams of DBTDL. A portion of this mixture wasloaded into a 30 cc disposable plastic syringe attached via a length of⅛-inch outside diameter Swagelok tubing to a sealed enclosure with aninside diameter of 1.5 inches and depth of 1 inch. This enclosure wasevacuated with a vacuum pump, and afterwards a valve was used to isolatethe pump from the tubing. The explosive was extruded by hand into thesealed and evacuated enclosure. A detonator (Reynolds RP-1) was attachedto the transparent polycarbonate top of the enclosure, with a 0.010-inchthick stainless steel layer between the detonator output pellet and theexplosive. The explosive was detonated; the heavy steel base of theenclosure formed a witness plate.

Example 17

A mixture of 50% by weight DAAF with 50% by weight GAP was loaded into atransparent poly(vinyl chloride) tube having an inside diameter of1-inch and length of 12 inches. Final density was 1.50 g/cc. This tubewas fitted with Dynasen PZT (lead titanate-zirconate) pins atwell-defined intervals to provide a measurement of detonation velocity.The tube was fitted with a Reynolds RP-1 detonator and booster pellet ofPBX9407 which was ½ inch in diameter and ½ inch long. Analysis of thedata showed a steady detonation with velocity of 6.80±0.01 kilometersper second.

Although the present invention has been described with reference tospecific details, it is not intended that such details should beregarded as limitations upon the scope of the invention, except as andto the extent that they are included in the accompanying claims.

What is claimed is:
 1. A method for extending a fracture network inrock, comprising: inserting an extrudable insensitive explosivecomposition into fissures in rock, the composition comprising aninsensitive explosive reaction product of a reaction between anexplosive diamine monomer and a monomer selected from an alkyldi-isocyanate monomer, an aryl di-isocyanate monomer, an alkylpoly-isocyanate monomer, an aryl poly-isocyanate monomer, or mixturesthereof, and thereafter detonating the composition, thereby extendingthe fracture network in the rock.
 2. The method of claim 1, furthercomprising a step of curing the composition prior to detonating thecomposition.
 3. The method of claim 1, wherein the explosive diaminemonomer is 3,3′-diamino-4,4′-azoxyfurazan.
 4. The method of claim 1,wherein the extrudable insensitive explosive composition furthercomprises a glycidyl azide polymer, hydroxyl-terminated polybutadiene,or mixtures thereof.
 5. The method of claim 1, wherein the aryldi-isocyanate monomer is selected from 4-di-isocyanato-1-methyl-benzene,1-isocyanato-4-[(4-isocyanatophenyl)methyl]benzene,1-isocyanato-2-[(2-isocyanatophenyl)methyl]benzene,1-isocyanato-2-[(4-isocyanatophenyl)methyl]benzene, ordi-isocyanato-containing isomers thereof.
 6. The method of claim 1,wherein the di-isocyanate monomer is3-isocyanatomethyl-3,5,5-trimethylcyclohexyl-di-isocyanate.
 7. Themethod of claim 1, wherein the insensitive explosive composition is aproduct of a chemical reaction of 4,4′diamino-3,3′-azoxyfurazan with adi-isocyanate monomer selected from3-isocyanatomethyl-3,5,5-trimethylcyclohexyl-di-isocyanate,2,4-diisocyanato-1-methyl benzene,1-isocyanato-4-[(4-isocyanatophenyl)methyl]benzene,1-isocyanato-2-[(2-isocyanatophenyl)methyl]benzene, and1-isocyanato-2-[(4-isocyanatophenyl)methyl]benzene.
 8. The method ofclaim 1, wherein the insensitive explosive composition is a product of achemical reaction of an explosive diamine monomer, a glycidyl azidepolymer, and an isocyanate-containing monomer selected from adi-isocyanate monomer, a poly-isocyanate monomer, or mixtures thereof.9. The method of claim 1 wherein the insensitive explosive reactioncomposition is a product of a chemical reaction of4,4-diamino-3.3′-azoxyfurazan monomer and a monomer selected from adi-isocyanate monomer, a poly-isocyanate monomer, or mixtures thereof.